HP SIM disk space reporting.

I have HP SIM 5.x with SP 4.Most of my servers are now updated upto 7.40A on the PSP packs.All reporting works brilliantly for events etc. BUT the disk space reports for the majority of the servers is not avaliable.When I add a server the disk space information is captured, but with in 2 hours it is lost. Is there any thing I can do to make the disk space capture more reliable? we want to use this for disk space reporting.